Bindings.fold

{- # Bindings -}


-- Value definition
val a = 1


-- Value definition with type annotation
val a :: Int = 1


-- Multiple recursive value definitions
val a = 1,
    b = c + a,
    c = a + 10


-- Function definition
def f a =
  a + 1


-- Function definition with block
def f a =
  let result = a + 1 in
  print "result = $result"



-- Function definition with type annotation
def f a :: Int -> Int =
  a + 1


-- Function definition with inline type annotation
def f (a :: Int) -> Int =
  a + 1


-- Function definitions with type declaration
def f :: Int -> Int
def f a = a + 1


-- Function definitions with pattern matching
def f 1 = 0
  | f a = a + 1


-- Function definition as a value
val f = a -> a + 1


-- [calculate_magic] prints a string representation of a magic number.
def calculate_magic () =
  let
    magic_number = 42 + fib another_regular_number,
    regular_number = 1,
    another_regular_number = 2

  let add_one x = x + 1

  let factorial n =
    match n
    | 0 -> 1
    | n -> n * factorial (n - 1)
    end

  let fib n =
    if n == 0 || n == 1 then 1
    else fib (n - 1) + fib (n - 2)

  in
    print ("The value of fib (magic_number + regular_number) is "
           ++ string (fib (magic_number + regular_number)) ++ "!")


val x =
  some_number + factorial 10
  where
    some_number = 23,
    factorial n =
      match n
      | 0 -> 1
      | n -> n * factorial (n - 1)
      end








-- * --


-- ### Semicolons for Definitions

let x = f x y z; e
  => let x = f x y z in e

f x y z; e
  => let () = f x y z in e


{- [calculate_magic] prints a string representation of a magic number. -}
fun calculate_magic () =
  val magic_number = 42 + fib another_regular_number,
      regular_number = 1,
      another_regular_number = 2,
      f x = 2

  fun add_one x = x + 1

  fun factorial n =
    match n
    | 0 => 1
    | n => n * factorial (n - 1)
    end

  fun fib 0 = 1
    | fib 1 = 1
    | fib n = fib (n - 1) + fib (n - 2)

  in
    print ("The value of fib (magic_number + regular_number) is "
           ++ string (fib (magic_number + regular_number)) ++ "!")



-- ## Let Expressions

let a = 1
print "The value of a is $a!"

let f a = a + 1
print "The value of (f a) is $(f 4)!"

let test () =>
  let
    a = 1

    f b = b + 1

    factorial =>
      match n
      | 0 -> 1
      | n -> n * factorial (n - 1)
      end

    factorial2 =
      | 0 -> 1
      | n -> n * factorial (n - 1),

    c = 3
  in
    print "The value of a, f b, c are $a, $(f 4), $c!"


-- ## Where Expressions

print "The value of a is $a!"
where a = 1

print "The value of (f a) is $(f 4)!"
where f a = a + 1

print "The value of a, f b, c are $a, $(f 4), $c!"
where
  a = 1

  f b = b + 1

  factorial n =
    match n
    | 0 -> 1
    | n -> n * factorial (n - 1)
    end

  factorial2 =
    | 0 -> 1
    | n -> n * factorial (n - 1),
  c = 3
end


-- * --
fun calculate_magic () =
  let magic_number = 42 + fib another_regular_number,
      regular_number = 1,
      another_regular_number = 2
  let add_one x = x + 1
  let factorial =
    match n
    | 0 => 1
    | n => n * factorial (n - 1)
    end
  let fib 0 = 1
    | fib 1 = 1
    | fib n = fib (n - 1) + fib (n - 2)
  in
    print ("The value of fib (magic_number + regular_number) is "
           ++ string (fib (magic_number + regular_number)) ++ "!")


let calculate_magic =
  let magic_number = 42 + fib another_regular_number,
      regular_number = 1,
      another_regular_number = 2
  let add_one x = x + 1
  let factorial =
    match n
    | 0 => 1
    | n => n * factorial (n - 1)
    end
  let fib
    | 0 | 1 => 1
    | n => fib (n - 1) + fib (n - 2)
  end in
  print ("The value of fib (magic_number + regular_number) is "
         ++ string (fib (magic_number + regular_number)) ++ "!")




def test () =>
  let
    magic_number = 42,
    regular_number = 1,
    fun add_one x => x + 1,
    fun factorial =>
      match n
      | 0 => 1
      | n => n * factorial (n - 1)
    c = 3,
    fun fib n =>
      | 0 | 1 => 1
      | n => fib (n - 1) + fib (n - 2)
  in
    print "The value of a, f b, c are $a, $(f 4), $c!"



-- StandardML style
def test () => let
  val a = 1

  fun f b = b + 1

  fun factorial =>
    match n
    | 0 -> 1
    | n -> n * factorial (n - 1)
    end

  fun factorial2 =>
    | 0 -> 1
    | n -> n * factorial (n - 1),

  val c = 3
in
  print "The value of a, f b, c are $a, $(f 4), $c!"


function test () =
  let
    a = 1

    f b = b + 1

    factorial =>
      match n
      | 0 -> 1
      | n -> n * factorial (n - 1)
      end

    factorial2 =>
      | 0 -> 1
      | n -> n * factorial (n - 1),

    c = 3
  in
    print "The value of a, f b, c are $a, $(f 4), $c!"


-- * --

module Person = ...

interface Comparable = ...

def hello name = ...

object
  def say_hello () =
    print
end


-- * --

-- StandardML
fun heron (a, b, c) = let
    val ab = dist (a, b)
    val bc = dist (b, c)
    val ac = dist (a, c)
    val perim = ab + bc + ac
    val s = perim / 2.0
    in
      Math.sqrt (s * (s - ab) * (s - bc) * (s - ac))
    end


def heron a b c =
  let
    ab    = dist (a, b)
    bc    = dist (b, c)
    ac    = dist (a, c)
    perim = ab + bc + ac
    s     = perim / 2.0
  in
    Math.sqrt (s * (s - ab) * (s - bc) * (s - ac))
  end

def heron a b c =
  Math.sqrt (s * (s - ab) * (s - bc) * (s - ac))
    where
      ab    = dist (a, b)
      bc    = dist (b, c)
      ac    = dist (a, c)
      perim = ab + bc + ac
      s     = perim / 2.0
    end


-- * --

var x = 0  -- let x = ref 0

macro var $name = $val
  $name = ref $val
end

x = ref 0

x!